​Marshawn Kneeland’s family has disclosed that the former Dallas Cowboys defensive end was diagnosed with early-stage chronic traumatic encephalopathy (CTE) after his death in November 2025. They say the diagnosis offers meaningful context about the struggles he may have faced and hope that sharing this information will help raise public awareness about the long-term consequences of repetitive head injuries in contact sports.
According to AP News, the diagnosis came from researchers at the Boston University CTE Center, who examined Kneeland’s brain tissue following his passing. Kneeland, who was 24 at the time of his death, was found to have Stage 1 CTE, the earliest stage of the disease’s four-stage progression. He died by suicide after a high-speed police pursuit in November 2025. CTE can only be confirmed posthumously and has been associated with repeated blows to the head experienced by athletes in contact sports, military veterans, and others exposed to chronic brain trauma. Researchers have linked the condition to a range of symptoms, including depression, impulsivity, and marked mood changes, although individual experiences vary.
In a statement released through the Concussion Legacy Foundation, Kneeland’s family—along with his girlfriend, Catalina Mancera—said the diagnosis helps illuminate some of the difficulties he may have endured. “While this diagnosis does not lessen the tragedy of his passing, it offers important context about the kinds of challenges he might have been facing. We are sharing this information to help people understand what NFL players and other high-contact-sport athletes may be dealing with.”
The family emphasized that their decision to publicize the findings aims to broaden awareness of the long-term effects of repetitive head injuries among football players and other athletes. “Raising awareness matters to us. We will always remember Marshawn with compassion for the person he was, rather than defining him by the final moments of his life. One Love.”
A Dallas Cowboys tribute image showed a shirt honoring Kneeland before a game against the Las Vegas Raiders in Las Vegas on November 17, 2025, featuring the inscription Marshawn Kneeland on the Cowboys’ logo. (AP Photo/David Becker)
The study results contribute to a growing body of research on the persistent neurological risks associated with repeated head impacts in football. The Boston University CTE Center has analyzed hundreds of donated brains from former athletes, fueling ongoing conversations about player safety, concussion protocols, and brain health across all levels of contact sports. While researchers continue to investigate CTE, experts reiterate that a definitive diagnosis cannot be made in living individuals.